Proteases are enzymes that cleave proteins. They occur widely in nature and serve a fundamental role in cellular homeostasis; however, their presence can result in unwanted protein degradation during recombinant protein expression and purification. This unit introduces proteases, specifically outlining the types commonly encountered during production of recombinant proteins. The strategies used to avoid and to prevent proteolysis are also highlighted with extensive consideration of the molecular, technical, and logistical methodologies involve
